1. Technical Field of the Invention
The present invention relates to a method for cleaning drainpipes in a movable equipment, and more particularly to, a method for cleaning a plurality of drainpipes installed at various locations in a movable equipment such as an airframe of a passenger airplane and connected to, for example, a washstand in a lavatory, a toilet seat and various solution storage tanks. The present invention also relates to an apparatus for cleaning such drainpipes.
2. Related Art
In a conventional cleaning method for cleaning drainpipes in a movable equipment, drainpipes to be cleaned are detached from the movable equipment, and carried to a place where a stationary cleaning apparatus is provided. Then, the drainpipes are set to the cleaning apparatus. After the cleaning, the cleaned pipes are detached from the cleaning apparatus and carried to a place where the movable equipment is stopping, and attached to the respective original portions in the movable equipment.
In a case where pipes equipped in a factory, which is not a movable equipment such as an airframe though, are cleaned by removing scale adhered to the inner surfaces of the pipes, the following high-pressure cleaning method was employed. In this cleaning method, impact force of speed energy converted from high-pressure energy is applied to the pipes while flowing a cleaning solution in the pipes in the discharge direction under pressure higher than a normal discharging pressure.
However, in the former cleaning method, considerable labor and time are required for detaching, carrying and attaching the pipes besides the cleaning operation itself. Therefore, in a case where drainpipes installed in a movable equipment, such as an airframe of a passenger airplane having many and complex drainpipes, are to be cleaned, enormous labor and cost are required for cleaning the drainpipes even in a single movable equipment. Accordingly, as an emergency cleaning method in a case where a drain capacity is reduced in between the periodic maintenance or an abrupt clogging of piping occurs, the aforementioned former cleaning method cannot be adopted when taking the required time and cost into consideration.
On the other hand, in the aforementioned high-pressure cleaning method, since the cleaning operation can be performed at any stopping place of the movable equipment such as an apron for a passenger airplane, both working labor and cleaning time can be reduced as compared with the aforementioned former cleaning method. However, even if an increased speed energy obtained by increasing the pressure is applied, it is very difficult to completely peel off adherent substances, such as scale, strongly adhered to the inner surfaces of the drainpipes because the cleaning solution is caused to flow in the same direction as that in normal use. Furthermore, a considerable time is required in order to perform the cleaning operation until a predetermined drain capacity is obtained, and frequent cleaning is also required for maintaining the predetermined drain capacity. In addition, since high pressure is applied to the drainpipes, leakage of the cleaning solution may occur at portions of the drainpipes where no leakage occurs under low pressure in normal use. Furthermore, with the progress of the cleaning operation under high pressure, normally concealed broken holes of the drainpipes may be exposed when adherent substances such as scale are removed, which causes leakage of a large amount of the cleaning solution.
An object of the present invention is to provide a method and an apparatus for cleaning drainpipes in a movable equipment, which can be performed at any place where a movable equipment is stopping with a reduced working labor and a greatly shortened cleaning time without causing any leakage of a cleaning solution while completely removing adherent substances such as scale in the drainpipes.
Another object of the present invention is to provide a method and an apparatus for cleaning drainpipes in a movable equipment, which can prevent a deterioration of a working environment and a peripheral environment due to a bad smell generated during the cleaning operation.
According to a first aspect of the present invention, a method for cleaning a plurality of drainpipes installed in a movable equipment by causing a flow of a cleaning solution through the drainpipes, the method including the steps of connecting provisional pipes to the respective drainpipes, feeding a cleaning solution into the provisional pipes and the drainpipes, and applying negative pressure suction force to the provisional pipes and the drainpipes to cause a flow of the cleaning solution in the opposite direction to a drain direction in normal use, to thereby clean the drainpipes.
According to a second aspect of the present invention, an apparatus for cleaning a plurality of drainpipes installed in a movable equipment by causing a flow of a cleaning solution through the drainpipes, the apparatus including provisional pipes to be connected to the respective drainpipes so as to allow a flow of a cleaning solution in the opposite direction to a drain direction in normal use, a cleaning solution preparation tank for preparing and storing the cleaning solution, a cleaning solution feeding pump for feeding the cleaning solution into the provisional pipes and the drainpipes, a vacuum pump for causing a flow of the cleaning solution filled in the provisional pipes and the drainpipes in the opposite direction by applying a negative pressure suction force to the provisional pipes and the drainpipes, a gas-liquid separation tank for separating the cleaning solution after having cleaned the drainpipes by flowing the cleaning solution in the opposite direction into gas components and liquid components, and a cleaning solution suction pump for returning the liquid components of the cleaning solution separated in the gas-liquid separation tank into the preparation tank.
According to the present invention as set forth above, the provisional pipes are connected to the respective drainpipes installed at various locations in a movable equipment, and the cleaning solution is caused to flow through the drainpipes in the opposite direction to a drain direction in normal use by applying a negative pressure suction force to the provisional pipes and the drainpipes. Therefore, it is possible to efficiently clean the plurality of drainpipes in a labor-saving manner at any place where the movable equipment is stopping. It is also possible to improve the ability for peeling off scale as compared with a high-pressure cleaning method because energy is exerted to the adherent substances such as scale, adhered to the inner surfaces of the drainpipes during a normal use, in the opposite direction to the growth direction of the adherent substances. Furthermore, the drainpipes are maintained under negative pressure during the cleaning operation. Therefore, leakage of the cleaning solution from the pipes can be assuredly prevented even if there is a pipe connection defects with no problem in normal use, and even if a small broken holes and the like are exposed by coming off the adherent substances such as scale with a progress of the cleaning operation.
Especially, the aforementioned cleaning method and apparatus can be effectively applied to an airframe of a passenger airplane which has many complex drainpipes and requires an emergency cleaning in case of a drain capacity reduction and a clogging of pipes which abruptly occur in between periodic maintenance. According to the method and apparatus, it is also possible to speedily perform a high quality cleaning of plurality of drainpipes so as to restore the predetermined drain capacity of the drainpipes without causing any leakage of the cleaning solution while parking the passenger airplane in a predetermined place.
In a case where the apparatus is equipped with a deodorization device for removing an odor of the gas components separated from the cleaning solution in a gas-liquid separation tank, it is possible to prevent a deterioration of a working environment and a peripheral environment by deodorizing a bad smell contained in a relatively large amount of gas components generated during the cleaning process of the drainpipes.
In a case where the apparatus includes a thermal expansion rubber seal member for sealing the gap between the outer peripheral portion of the provisional pipe inserted into the drainpipe from an opening portion thereof and the inner peripheral portion of the opening portion so that the negative pressure suction force can be applied to the drainpipes, a connection of these pipes becomes very simple and a preliminary work for cleaning can be performed easily and speedily. Furthermore, at a time of cleaning, a negative pressure due to the vacuum suction force can be applied to the drainpipes through the provisional pipes without a loss, so that it is possible to assuredly perform a predetermined cleaning of the drainpipes by the reverse flow of the cleaning solution.
Furthermore, in a case where each component of the apparatus except for the provisional pipe, is mounted on a vehicle body and the apparatus as a whole is constituted as an explosion-protection structure, it is possible to enlarge a scope of an applicable movable equipment to which a quick, effective and safety cleaning of the drainpipes by the cleaning apparatus can be performed.
Other objects and advantages of the present invention will become apparent from the description of the preferred embodiments, which may be modified in any manner without departing from the scope and spirit of the present invention.